Use a shovel or spade to dig a hole that is twice as wide as the container and equally deep. If the site has poor drainage then it is a good idea to dig the hole deeper and then backfill it with native soil to the appropriate depth.
If the sides of the hole have become smooth, then scrape them rough to remove a potential barrier to root and water movement.
Gently remove the plant from its container. For heavier plants, it may be necessary to lay the plant on the ground and slide the container off. It may also be necessary to loosen the soil by squeezing the sides of the container.
Gently loosen any roots that have become root-bound. If the roots are extremely tangled, then it may be necessary to score the root ball a few times with a sharp utility knife.
Ensure that the soil height at the bottom of the hole is such that the plant will sit level or slightly above the existing grade. Place the plant into the hole. Do not install the plant deeper than the current soil level.
Gently backfill around the plant, firming the soil around it as you go. Regularly check to ensure that the plant is straight. Finish with a berm or small ridge around the plant to hold water.
Water the plant thoroughly.
Apply three to four inches of mulch around the base of the plant. Ensure that the mulch does not come into contact with the plant.